Figure 1. Effect of various mixes of facilitation and competition on the within-host dynamics of coinfecting species. A,

Equilibrium densities of parasite A (A*). B, Equilibrium densities of parasite B (B*). C, Virulence such that V = aA*+bB*. The red region represents the region where all equilibria are destabilized (i.e. xy>z, x<0 and y<0). Darker regions indicate lower values. The values on the contour lines indicate the relative densities of parasite at equilibrium. The line x = 0 defines the density of parasite A alone, and y = 0 defines the density of parasite B alone. The parameter values used are a = b = z = 1.